The present invention relates to a method of manufacturing a layer-built material in which a silicon dioxide film containing an organic colorant is formed on a substrate, and to the layer-built material manufactured thereby.
As a means for acquiring a material having new functional feature, it is already attempted to introduce an organic colorant to a silicon dioxide film. However, organic colorants are easily decomposed when being exposed to high temperatures and, therefore, a so-called sol-gel method is the only method conventionally practiced for producing such material featuring new functional characteristic. Typically a technical paper "J. Non-Crys. Solids, 74 (1985), 395" refers to this method in which a fluorescent organic colorant is introduced to silicon dioxide film. This prior art reports to have merely produced a porous film containing organic colorant. Another technical paper "Ceramics, 21, No. 2, 1986, 111" proposes the doping of organic molecules into non-crystal quartz by sol-gel method. It is reported that residual impurities, distortion, defects and the like are present in the structure of the produced glass.
Any of those prior arts use the sol-gel method, and as a result, in order to securely fix the film to the substrate, heating must be executed in the final stage of the production process. However, since the film on the substrate cannot be heated at such a high temperature as causing the organic colorant to decompose, the resultant film unavoidably becomes porous. Furthermore, organic colorants easily decomposable by heating at a low temperature cannot be used in this method. Heating which is obliged to conduct at a low temperature raises further problems inherent to the sol-gel method, for example, generation of residual impurities in the structure of film such as some amounts of undecomposed raw material and organic solvent. These prior arts cited above commonly involves another problem of expensive cost of film because expensive metal alkoxide is used as the starting material. Furthermore, dip-coating employed by those prior arts cannot effectively be applied to substrates having complex form.
The primary object of the invention is to provide a novel method of manufacturing a silicon dioxide film containing an organic colorant which is perfectly free from those defects inherent to any conventional method of manufacturing silicon dioxide film containing organic colorant.
The term "organic colorant" as used herein means a concept broad enough to include those capable of developing color by any effective treatment.
The first embodiment of the invention relates to a method of dyeing a molded organic material. More particularly, it relates to a method of forming a colored layer featuring surpassing chemical and mechanical durability on the surface of molded organic material shaped in those forms such as plane sheet, film, rod, tube, sphere, fiber, web, and a variety of processed forms.
Conventionally, the molded organic material is colored merely by adding colorant to the organic material in the course of synthesizing the moldable material. For example, when coloring moldable resin, any of those colorants such as inorganic pigment, or organic pigment, or dyestuff, is blended with resin, and then pasted, uniformly dispersed in the resin, which is then polymerized and cured before eventually being molded. However, the method of blending colorant with moldable organic material is subject to restriction against molding temperature of resin, polymerizing and curing condition, and crosslinking condition caused by weak heat resistivity of the organic colorant and has a problem against the weatherability in exposure to air and water. In addition, there is a certain limit caused by inability to locally color on the moldable object.
To dispose of those problems, in addition to the method of blending colorant with moldable organic material mentioned above, conventionally, either printing or dyeing process is used for coloring on the surface of the moldable organic material. Printing is performed by causing color ink composed of either inorganic pigment, or organic pigment, or dyestuff, to be absorbed into the moldable organic material. Printing process locally colors the molded substrate, and in addition, there are a variety of kinds of colors available for coloring the molded substrate. However, adhesive strength of colorant contained in ink for molded substrate having smooth surface is weak, so that ink film often exfoliates. Furthermore, since the surface of molded substrate does not absorb ink vehicle, it is necessary that vaporization of organic solvent is promoted by heating. Nevertheless, since heating process at a high temperature cannot be applied, organic solvent may remain on the printed surface to result in the occurrence of odor and blocking (i.e., adhesion of the printed substrates).
On the other hand, dyeing is mainly used for coloring fibers by causing colorant mainly consisting of dyestuff to be absorbed into fibers. In case of dyeing fibers, in order to promote the bonding force between dyestuff and fibers, it is necessary to carefully select dyestuff, auxiliary agents, and paragenic ion and the like in accordance with fibers, so that dyeing process becomes extremely complex.
Furthermore, printing and dyeing have common problems. Colorant is directly exposed to external atmosphere, and as a result, oxygen and moisture in atmosphere easily causes oxidation and hydrolysis to occur. In addition, rendering symptom may also be generated due to presence of water, organic solvent, and a variety of chemicals. Also, dyed fibers may mechanically be worn or damaged, so that local degradation of the colored effect or local discoloration often occurs.
The primary object of the first embodiment of the invention is to fully eliminate those defects inherent to the printing and dyeing processes mentioned above by providing an improved coloring or dyeing method which is capable of securely forming a colored layer on the surface of the molded organic substrate and features surpassing chemical and mechanical durability.
More particularly, the invented method dispenses with the condition of causing the colorant to be exposed to the external atmosphere directly while either the printing or the dyeing is underway, and the invented method prevents the colorant from reacting water and organic solvent by virtue of the protective effect of silicon dioxide film, thus securely promoting the weatherability of the colored layer. Furthermore, by virtue of surpassing durability of silicon dioxide against wear, the durability against mechanical wear is also promoted. Since the improved method of the first embodiment of invention provides organic silicon compound (coupling agent) between silicon dioxide containing colorant and the molded organic substrate, the bonding force between the colored layer and the molded organic substrate is intensified.
As is clear from the above description, the object of the first embodiment of the invention is to provide a colored layer which has extremely intense bonding force on the surface of the molded organic substrate and the chemically and mechanically stable resistivity by initially forming a film of organic silicon compound (coupling agent) before eventually generating silicon dioxide film containing colorant.
The second embodiment of the invention relates to a method of coloring acrylic resin molded substrate. More particularly, it relates to a method of forming a chemically and mechanically durable colored layer on the surface of the molded acrylic resin shaped in those forms such as plane sheet, film sheet, rod, tube, sphere, fiber, web, and a variety of processed forms.
Conventionally, colorant is added to the molded acrylic resin in the course of synthesizing the moldable material. For example, when coloring molded resinous material, any of those coloring agents such as inorganic pigment or organic pigment, or dyestuff, is blended with resin, which is then pasted, and then uniformly dispersed in the resin material, which is then polymerized and cured before eventually being molded. However, the method of blending colorant with moldable acrylic resin is subject to restriction against molding temperature of resin, polymerizing and curing condition and crosslinking condition caused by weak heat resistivity of the organic colorant, and has a problem against the weatherability in exposure to air and water. In addition, there is a certain limit when using colorant caused by inability to locally develop color on the moldable material.
To dispose of those problems, in addition to the method of blending colorant with moldable acrylic resin mentioned above, conventionally, either printing or dyeing process is widely used for coloring on the surface of the moldable acrylic resin. Printing is performed by causing color ink composed of either inorganic pigment or organic pigment, or dyestuff, to be absorbed into the moldable organic material surface. Printing allows the molded substrate to be colored locally, and in addition, there are a variety of kinds of colors available for coloring. However, adhesive strength of colorant contained in ink for molded substrate having smooth surface is weak, so that ink film often exfoliates. Furthermore, since the surface of the molded resin does not absorb ink vehicle, it is necessary that vapourization of solvent is promoted by the heating. Nevertheless, since the heating process at a high temperature cannot be applied, organic solvent may remain oh the printed surface to result in the occurrence of odor and blocking (i.e., adhesion of the printed substrates).
On the other hand, dyeing is mainly used for coloring fibers by causing colorant mainly consisting of dyestuff to be absorbed into fibers. When dyeing fibers, in order to promote the bonding force between dyestuff and fibers, it is necessary to carefully select dyestuff, auxiliary agents, and paragenic ion, and the like in accordance with fibers, so that dyeing process becomes extremely complex.
Furthermore, printing and dyeing have common problems. Colorant is directly exposed to external atmosphere, and as a result, oxygen and moisture in atmosphere easily causes oxidation and hydrolysis to occur. In addition, rendering symptom may also be generated due to presence of water, organic solvent, and a variety of chemicals. Also, dyed fibers may mechanically be worn or damaged, so that local degradation of the colored effect or local discoloration often occur.
The object of the second embodiment of the invention is to fully eliminate those defects inherent to the printing and dyeing processes mentioned above by providing an improved coloring or dyeing method which is capable of securely forming colored layer on the surface of molded acrylic resin and features surpassing chemical and mechanical durability.
More particularly, the invented method dispenses with the condition of causing the colorant to be exposed to the external atmosphere directly while either the printing or the dyeing process is underway, and the invented method prevents the colorant from reacting water and organic solvent by virtue of the protective effect of silicon dioxide film, thus securely promoting the weatherability of the colored layer. Furthermore, by virtue of surpassing durability of silicon dioxide against wear, the durability against mechanical wear is also promoted. Since the improved method provides organic silicon compound (coupling agent) between silicon dioxide containing colorant and the molded acrylic resin, the bonding force between the colored layer and the molded acrylic resin is intensified.
As is clear from the above description, the object of the second embodiment of the invention is to provide a colored layer which has extremely intense bonding force on the surface of the molded acrylic resin and the chemically and mechanically stable resistivity against wear by initially forming a film of organic silicon compound (coupling agent) before eventually generating silicon dioxide film containing colorant.
The third embodiment of the invention relates to a method of coloring polycarbonate resin molded substrates. More particularly, it relates to the method of forming a chemically and mechanically durable colored layer on the surface of the molded polycarbonate resin shaped in those forms like plane sheet, film, rod, tube, sphere, fiber, web, and a variety of processed forms.
Conventionally, colorant is added to the molded polycarbonate resin in the course of synthesizing the moldable material. For example, when coloring molded resinous material, any of those coloring agents like inorganic pigment or organic pigment, or dyestuff, is blended with resin, which is then pasted, and then uniformly dispersed in the resin material, which is then polymerized and cured before eventually being molded. However, the method of blending colorant with moldable polycarbonate resin is subject to restriction against molding temperature of resin, polymerizing and curing condition, and crosslinking condition caused by weak heat resistivity of the organic colorant, and has a problem against the weatherability in exposure to air and water. In addition, there is a certain limit when using colorant caused by inability to locally develop color on the moldable material.
To dispose of those problems, in addition to the method of blending colorant with moldable polycarbonate resin mentioned above, conventionally, either printing or dyeing process is widely used for developing color on the surface of the moldable polycarbonate resin. Printing is performed by causing color ink composed of either inorganic pigment, organic pigment, or dyestuff, to be absorbed into the moldable organic material surface. Printing allows the molded substrate to be colored locally, and in addition, there are a variety of kinds of colors available for coloring. However, adhesion strength of colorant contained in ink for mold substrate having smooth surface is weak, so that ink film often exfoliates. Furthermore, since the surface of the molded resin does not absorb ink vehicle, it is necessary that vapourization of solvent be promoted by the heating. Nevertheless, since the heating process at a high temperature cannot be applied, organic solvent may remain on the printed surface to result in the occurrence of odor and blocking (i.e., adhesion of the printed substrates).
On the other hand, dyeing is mainly used for coloring fibers by causing colorant mainly consisting of dyestuff to be absorbed into fibers. When dyeing fibers, in order to promote the bonding force between dyestuff and fibers, it is necessary to carefully select dyestuff, auxiliary agents, and paragenic ion, and the like in accordance with fibers, so that dyeing process becomes extremely complex.
Furthermore, printing and dyeing have common problems. Colorant is directly exposed to external atmosphere, and as a result, oxygen and moisture in atmosphere easily causes oxidation and hydrolysis to occur. In addition, rendering symptom may also be generated due to presence of water, organic solvent, and a variety of chemicals. Also, dyed fibers may mechanically be worn or damaged, so that local degradation of the colored effect or local discoloration often occurs.
The object of the third embodiment of the invention is to fully eliminate those defects inherent to the printing and dyeing processes mentioned above by providing an improved coloring or dyeing method which is capable of securely forming colored layer on the surface of molded polycarbonate resin and features surpassing chemical and mechanical durability.
More particularly, the invented method dispenses with the condition of causing the colorant to be exposed to the external atmosphere directly while either the printing or the dyeing is underway, and the invented method prevents the colorant from reacting water and organic solvent by virtue of the protective effect of silicon dioxide film, thus securely promoting the weatherability of the colored layer. Furthermore, by virtue of surpassing durability of silicon dioxide against wear, the durability against mechanical wear is also promoted. Since the improved method of the third embodiment of the invention provides organic silicon compound (coupling agent) between silicon dioxide containing colorant and the molded polycarbonate resin, the bonding force between the colored layer and the molded polycarbonate resin is intensified.
As is clear from the above description, the object of the third embodiment of the invention is to provide a colored layer which has extremely intense bonding force on the surface of the molded polycarbonate resin and the chemically and mechanically stable resistivity against wear by initially forming a film of organic silicon compound (coupling agent) before eventually generating silicon dioxide film containing colorant.
The fourth embodiment of the invention relates to coloring pigments which form a colored layer on the surface of pulverulent body. More particularly, it relates to a coloring pigments which form silicon dioxide film containing organic colorant on the surface of pulverulent body and features surpassing chemical and mechanical durability.
Today, important role of pigment sharply increases as versatile colorant for the production of paint, printing ink, cosmetics, synthetic resin, and conventional goods in a variety of fields.
Pigment consists of inorganic pigment made from inorganic material and organic pigment made from organic material. Most of inorganic pigments are chemically stable and harmless, which are extensively used for the production of paint, printing ink, cosmetics, and construction materials.
On the other hand, only limited kinds of inorganic pigments are available today. In particular, the inorganic pigment lacks in the color brilliancy. As a result, in many cases, organic pigments are unavoidably used for the production of those fields of goods critically requiring color characteristic, for example, makeup cosmetics including lip stick and nail enamel for the point makeup, or image printing ink. Although organic pigments feature a wide variety of the kinds of color and brilliancy of color, majority of them are based on tarry ingredient. Because of potential hazard against human health like skin disease, carcinogenic potential, or mutation, strict regulation is legally applied to the use of organic pigments. And therefore, there is substantial restriction over the use of organic pigments today.
To deal with those problems cited above, a wide variety of attempts such as coating the surface of organic pigment completely with inorganic material and sealing organic pigment inside of extremely fine inorganic capsules were tried. Nevertheless, in strict sense, such protective layer made from inorganic material consists of crusted structure composed of porous or extremely fine colloid, so that the protective layer cited above cannot fully prevent organic pigment from coming into contact with water, solvent, and oxygen.
More particularly, there is no practical means to safely materialize such chemically stable pigments featuring a wide variety of available colors and color brilliancy.
The object of the fourth embodiment of the invention is to fully solve those problems inherent to conventional coloring pigments by forming silicon dioxide film containing organic colorant all over the surface of inorganic or organic pulverulent body so that stability and safety of this film comparable to those of inorganic pigments can be achieved while securing abundant kinds and brilliancy of colors characteristic of organic pigments.
The fifth embodiment of the invention relates to a color filter necessary for a light-receptive display device like liquid crystal display (LCD). More particularly, it relates to a color filter which features surpassing chemical and mechanical durability and is provided with the color layers of red, green, and blue composed of silicon dioxide film containing organic colorant.
As a result of significant development achieved in the information/communication fields, display device shares extremely important roles. Accordingly, there are a variety of sophisticated demands on the display technique to materialize light weight, slim structure, wider area, coloration, and finer image for the display device. In particular, there is a growing expectation on the LCD which has achieved significant technological progress in late years. Above all, there is an ardent expectation on the liquid crystal color display like a color TV for example. To suffice the demand, a variety of arts related to the color liquid crystal display have already been proposed.
Today, majority of the colored liquid crystal display devices incorporate color filters which at regular intervals set fine color layers of red (R), green (G), and blue (B) in the order of RGB, RGB . . . . In order to select any of these RGB colors at a specific display position, shutter function of liquid crystals operating in correspondence with extremely fine areas of the RGB colors is used.
At present, some methods have been tried for the production of the color filter cited above. One of these methods directly coats the three-color inks over the surface of glass by applying the offset or screen printing process for each color for three rounds. Despite of simple process, precision of the printed pattern is critical problem. Furthermore, ink thickness becomes thick in the portion where these three-color inks are superimposed. As a result, the ink surface easily generates concaves and convexes. To level off the surface, leveling operation is necessary. Normally, surface smoothening operation is necessarily performed by coating, for example, polyimide resin film over the surface coated with R, G, and B inks. Conventionally, printing ink is composed of the blend of organic solvent like "cellosolve" and colorant like organic colorant and pigment. Also, leveling agent is composed of organic material. After completing the smoothening operation, transparent electrodes composed of indium oxide/zinc indium (ITO), film, for example, are provided under vacuum condition. While forming this film, organic material arises problems such as long time pressure reduction operation caused by discharge gas from the material, and difficulty of obtaining satisfactory ITO film. To dispose of this problem, there is another method which initially forms silicon dioxide film on the surface of the leveling agent by applying sputtering process before eventually generating the ITO film.
The secondary method coats photopolymer containing organic colorant over the ink surface by applying photoresist process. For example, ink surface is initially masked by the photoresist process except for the red-ink portion, and then, photopolymer containing red colorant is coated over the red segment, and finally, photopolymer is optically cured before a red filter is eventually formed. Next, masking agent is removed, and then, by repeating those sequential processes against the green and blue segments as is done for the red segment before a color filter is eventually produced.
The above method involves a number of processes because delicate operation like the photoresist process must be performed repeatedly with much care. On the other hand, advantage of this method is that extremely precise pattern is obtained. However, even when applying this method with the photoresist process, the surface of the colorant applied to the red, green, and blue components becomes unlevel to a certain extent, so that, after executing this method, the leveling process is required. Furthermore, as was done for the printing process, since the photopolymer and the leveling agent are respectively composed of organic material, after completing the leveling process, it is necessary that silicon dioxide film is formed in the final stage.
The third method preliminarily forms patterned ITO film on the transparent substrate in correspondence with the red, green and blue components, and then immerses the substrate in aqueous solution containing dispersed organic pigments. Next, DC voltage is supplied between opposite electrodes like graphite electrodes and the red segment on the surface of the substrate in the aqueous solution to allow only the red organic pigment (having colloidal electric charge in this solution) to be laid on the surface of the red segment. Next, green organic pigment is laid on the surface of the ITO film of green segment by supplying DC voltage between those opposite electrodes and the ITO film of the green segment in aqueous solution containing dispersed green organic pigment. These serial processes are also executed against the blue segment Even in this method, after completing those sequential processes mentioned above, it is necessary that the leveling process is performed before eventually forming the silicon dioxide film as was done for the first and second methods mentioned earlier.
As is clear from the above description, any of those methods attempted needs to individually perform coating processes for the red, green, and blue segments, and yet, since the leveling process for leveling uneven thickness of film after completing the coating process solely uses organic material like organic colorant and organic leveling agent, any of those methods cited the above needs to form silicon dioxide film in order to restrain discharge of gas in presence of vaccum. Above all, too many steps and the complexity of these processes are critical problems to solve for reducing the production cost. Thus, an early renovation of these methods cited the above is urged today.
The fifth embodiment of the invention has been achieved to fully solve those problems related to color filters. The object of the fifth embodiment of the invention is to dispense with the process for forming silicon dioxide film thus far needed for restraining discharge of gas under vacuum condition and also eliminate the leveling process by providing a novel means for forming silicon dioxide film containing organic colorant.
The sixth embodiment of the invention relates to a colored mirror composed of a colored layer which is formed on the surface of a transparent substrate. More particularly, it relates to a colored mirror featuring surpassing durability against chemical and mechanical wear, where the colored mirror is composed of silicon dioxide film containing organic colorant on the surface of a transparent substrate.
From those old days, there is a constant demand for such a colored mirror to enhance the decorative effect. Recently, there is an idea of applying the colored mirror to the filter mirror by availing of the effect of the increase and decrease of reflection rate in the specific wave length band shown in the spectrum of the colored mirror.
When using the colored mirror for decorative purpose, coloration is performed by either coloring the transparent substrate itself or forming the colored layer on the transparent substrate. In the method, basically, coloration of the transparent substrate is performed by blending colorant with the substrate material, although there is difference in the colored effect depending on the kinds of material available for the substrate. For example, trial coloration of glass substrate was executed by blending inorganic colorant with the substrate material while the glass production process was underway. Also, trial coloration of plastic substrate was executed by blending colorant such as organic dyestuff or organic pigment with resinous material while the plastic molding process was underway.
Nevertheless, there were a variety of restrictive factors in the coloration of glass substrate using inorganic colorant, where the restrictive factors were found in the limited kinds of colors for use, absence of color brilliancy, inability of coloration against part of the substrate, etc. On the other hand, although there are a wide variety of colors having satisfactory brilliancy available for coloring resinous material containing organic colorant, the colored plastic substrate still has problem common to organic materials, where the problem is found in the shortage of chemical durability against water and oxygen which respectively infiltrate into the plastic substrate, shortage of physical durability against ultraviolet rays, and inability to implement local decoration. As a result, like the coloration of glass substrate, there is substantial restriction over the application of the method of coloring plastic substrate.
To dispose of this problem, a method of forming metallic film over the colored layer preliminarily formed on the surface of the transparent substrate has widely been introduced. Although this method allows local coloration, like the case of coloring the glass substrate mentioned above, there is a certain limit in the kinds and brilliancy of available colors. (When producing glass substrate, generally, colored layer is formed with inorganic colorant like the case of providing colored luster.) As a result, trials are still underway for forming organic colored layer over the surface of plastic substrate. Nevertheless, since organic colorant is present in the surface layer of plastic substrate, durability and weatherability are more critical problems than the coloration of the plastic substrate itself.
Furthermore, the filter mirror generally requires not less than three layers, so that it arises such problems as difficulty of applying to large scale substrates because of troublesome film thickness control and high production cost brought by many production steps.
The sixth embodiment of the invention has been achieved to fully solve those problems related to the conventional colored mirrors. The object of the sixth embodiment of the invention is to provide a novel colored mirror featuring extremely high durability and weatherability, availability of a wide variety of colors, brilliancy of colors, and the local coloration capability, by providing novel silicon dioxide film containing organic colorant on the surface of transparent substrate.
The seventh embodiment of the invention relates to a glass composed of colored layer coated on a glass substrate having unlevel surface. More particularly, it relates to a colored glass having enhanced decorative function by forming novel silicon dioxide film containing organic colorant on the unlevel surface of the glass substrate.
In order to promote decorative function of glass, template glass having figurative patterned unlevel surface has been used since old days. Furthermore, in order to promote glare-proof effect and restrain transparency of glass, an art of roughing the glass surface has widely been made available. For example, ground glass having the surface ground with a metallic brush is exemplified. In addition, there is such an art of roughing the glass surface by applying sand-blast process and an art of etching the glass surface by applying a sort of hydrofluoric acid solution. In this way, glass having unlevel surface is widely used for a variety of purposes like for decoration, restraining transparency, and for achieving glare-proof effect.
Recently, a variety of trials are actively carried on to promote decorative effect and appearance by coloring those kinds of glass mentioned above so that more comfortable living space can be materialized. Mainly, two methods are experimentally performed to color glass having unlevel surface. One is an art which varies the composition of glass before being colored. For example, oxide composed of transition metal like cobalt, nickel, iron, or chrome, is added to glass material so that the glass material can be colored by the ionized effect of those metallic elements mentioned the above. While the colored glass material still remains in the softened state during molding, a pattern on the glass surface is engraved using a roll bearing figurative unlevel pattern before eventually producing template glass. Nevertheless, only those cold colors including blue, green, yellow, and gray can be used for developing color when applying the above method. Furthermore, there are only limited kinds of colors available for this method. Above all, since glass material containing colorant is dissolved in the glass furnace, this method is not suited for producing a variety of kinds of colored glass in small production lots. To dispose of these problems, another method was tried for forming transparent layer on unlevel surface of glass. A thermal discomposition method, as is typically represented by luster for example, wherein the glass initially coated with organic solvent solution containing organic metal compound and precious metal compound, and then applied heat treatment between 450.degree. C. and 550.degree. C. A still another method was also attempted by initially coating paste containing precious metal compound of gold, silver, and copper on the plane glass, followed by thermal treatment between 500.degree. C. and 600.degree. C., and impregnation of precious metal elements into glass by ion-exchange process before eventually developing color.
Any of those methods cited above utilizes color development of metallic colloid. Thermal decomposition method causes precious metal colloid to be generated in metal oxide, whereas ion-exchange method causes precious metal colloid to be generated on the glass surface layer. Nevertheless, any of these methods merely uses limited kinds of colors effective for development, and yet, only those cold colors cited above are applicable. Above all, a critical problem of any of these methods like spraying or immersing process is that colored layer having uniform thickness cannot be formed because of the unlevel glass surface. In other words, any of these methods cannot practically be used because the colored effect is significantly uneven.
The seventh embodiment of the invention has been achieved to fully solve those problems inherent to the art of colored glass having unlevel surface. The object of the seventh embodiment of the invention is to provide such colored glass free from those problems mentioned the above, where the colored glass provided by the seventh embodiment of the invention has chemically and mechanically stable colored layer by applying a wide variety of available colors and brilliancy of these colors characteristic of organic colorant by allowing novel silicon dioxide film containing organic colorant to stably be formed on the glass surface.
The eighth embodiment of the invention relates to metallic substrate which is complete with coloration process. More particularly, it relates to such metallic substrate which is provided with colored layer featuring surpassing durability and decorative effect by forming novel silicon dioxide film containing organic colorant on its surface.
To enhance decorative effect of any metallic substrate, conventionally, colored layer has been formed on its surface since old days. For example, the chemical coloration process represented by the black-dyeing method immerses the metallic substrate in aqueous solution containing potassium sulfide or potassium persulfate for sulfuration or oxidation of the metallic surface so that the blackening characteristic of the sulfurated or oxidized layer can be used. This method is applicable to such metallic substance like copper, iron, and aluminium. However, this method is not always widely applicable, and yet, only black is available for development. To compensate for this, anode oxidation method is widely applied today, which is effective for such metal like stainless steel that cannot be colored merely by applying chemical coloration process. Anode treatment of aluminium is the typical example of the anode oxidation method, where aluminium can be colored by contacting the aluminium with solvent containing organic dyestuff, although the oxidized layer formed is porous and colorless.
In addition, although porous colored layer can be formed on the surface of metallic substrate by treatment with phosphate or chromate, only limited number of the kinds of color are applicable, and therefore, only organic dyestuffs are unavoidably used. However, coloring the metal substrate with porous layer, containing colorant, formed by anode oxidation process or chemical treatment has drawbacks:
most of the formed layers are opaque so that metal surface becomes invisible;
coloring process is complex since sealing process for pinholes is required after impregnating these pinholes with dyestuff; and
dyestuffs are easily disgraded and discolored by water infiltrating through sealing wall. In addition, metallic substrates which can be applied to by the above-mentioned treatment are limited. As a result, it is difficult to adopt the above-mentioned method as a universal method.
To replace those methods cited above, another method was also tried. This method colors the metal surface by generating eutectoid of metallic particles and molecules of organic and inorganic pigments by applying dispersion plating process. Also in this case, there is a restriction in practical application since the coated layer becomes too thick for the metal surface to be seen, and insufficient acidproof of the eutoctoid-applied metallic particle.
As mentioned above, although it was the important target for the concerned to properly coat the metal surface with optional colors during the past years, actually, there was no art that could satisfy this requirement because of a variety of problems in the kinds of available colors, kinds of usable metals, and the durability of colored layer.
The object of the eighth embodiment of the invention is to provide novel metallic substrate which fully solves those problems found in any of these prior arts.
The ninth embodiment of the invention relates to a glass covering clocks and/or wrist watches. More particularly, it relates to a colored glass covering clocks and/or wrist watches, which features provision of sufficiently strengthened glass covering with transparent layer on the surface.
To enhance decorative function of clocks and wrist watches, a variety of trials were carried out for coloring the covering glass since old days. One of these methods is to blend the glass material with oxide of transition metal like cobalt, nickel, iron, and chrome so that glass material can be colored by ionized effect of these metallic elements Nevertheless, this method can merely use those limited kinds of cold colors including blue, green, yellow, and gray for development, and yet, there are only limited kinds of colors available for this method. In particular, since glass material containing colorant is dissolved in the glass furnace, this method is not suited for producing a variety of kinds of clock/watch covering glass in small production lots. To dispose of this problem, another method was tried, in which initially transparent colored layer on plane glass was formed, and then, thermal treatment was applied before eventually performing molding process. To form a colored layer, as typically shown by luster, thermal decomposition method wherein a plane glass is coated with organic solvent solution containing organic metal compound and precious metal compound, and then they are applied with thermal treatment between 450.degree. C. and 550.degree. C. Another method was also tried, which initially coated the plane glass with paste containing precious metal compound like gold, silver, or copper, and then it was applied with thermal treatment between 500.degree. C. and 600.degree. C., and then precious metal element was impregnated into the glass by applying ion-exchange process before eventually developing color.
Any of those preceding methods effectively uses color development of metallic colloid. The thermal decomposition method allows generation of precious metal colloid in metal oxide, whereas the ion-exchange method allows generation of precious metal colloid in the glass surface layer. Nevertheless, when applying either of these methods, only limited kinds of colors are available for the color development, and yet, only those cold colors cited above are available. In particular, any of these preceding methods has a critical problem, that is, chemical strengthening for covering glass cannot be applied to those method.
More particularly, when executing any of those methods cited above, the covering glass is chemically strengthened by being immersed in the heated nitrate solution containing K.sup.+ so that Na.sup.+ can be exchanged with K.sup.+ in the nitrate solution. However, the colored layer which was colored by preliminarily applying either the thermal decomposition method or the ion-exchange method against the glass surface disturbed the transfer of the Na.sup.+ and K.sup.+, so that it was not possible for these methods to properly exchange ion for chemically strengthening the glass surface. To dispose of this defect, trials were executed for coloring glass surface chemically strengthened. However, since the strength was lowered by the thermal treatment executed for the coloring process, the method were not practically adopted.
A still another trial wherein organic solvent containing organic colorant is coated with the chemically strengthened glass, for example, the sol-gel method was tried. Nevertheless, the trial failed to evenly form colored layer having uniform thickness on a variety of shapes of the covering glass. Namely, depending on the shape of the covering glass, the colored effect was uneven, and yet, organic colorant proved to be poor in the durability.
As mentioned above, it was quite difficult for any conventional art to properly form durable color layer under a low temperature by chemically strengthening the covering glass having various shapes without sacrificing own strength of the colored layer.
The object of the ninth embodiment of the invention is to provide a novel covering glass free from those technical problems mentioned above.